From: Bob Peterson rpeterso@redhat.com
[ Upstream commit 5fcff61eea9efd1f4b60e89d2d686b5feaea100f ]
Before this patch, functions gfs2_qa_get and _put used the i_rw_mutex to prevent simultaneous access to its i_qadata. But i_rw_mutex is now used for many other things, including iomap_begin and end, which causes a conflict according to lockdep. We cannot just remove the lock since simultaneous opens (gfs2_open -> gfs2_open_common -> gfs2_qa_get) can then stomp on each others values for i_qadata.
This patch solves the conflict by using the i_lock spin_lock in the inode to prevent simultaneous access.
Signed-off-by: Bob Peterson rpeterso@redhat.com Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/gfs2/quota.c | 32 ++++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c index 6e173ae378c4..ad953ecb5853 100644 --- a/fs/gfs2/quota.c +++ b/fs/gfs2/quota.c @@ -531,34 +531,42 @@ static void qdsb_put(struct gfs2_quota_data *qd) */ int gfs2_qa_get(struct gfs2_inode *ip) { - int error = 0; struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); + struct inode *inode = &ip->i_inode;
if (sdp->sd_args.ar_quota == GFS2_QUOTA_OFF) return 0;
- down_write(&ip->i_rw_mutex); + spin_lock(&inode->i_lock); if (ip->i_qadata == NULL) { - ip->i_qadata = kmem_cache_zalloc(gfs2_qadata_cachep, GFP_NOFS); - if (!ip->i_qadata) { - error = -ENOMEM; - goto out; - } + struct gfs2_qadata *tmp; + + spin_unlock(&inode->i_lock); + tmp = kmem_cache_zalloc(gfs2_qadata_cachep, GFP_NOFS); + if (!tmp) + return -ENOMEM; + + spin_lock(&inode->i_lock); + if (ip->i_qadata == NULL) + ip->i_qadata = tmp; + else + kmem_cache_free(gfs2_qadata_cachep, tmp); } ip->i_qadata->qa_ref++; -out: - up_write(&ip->i_rw_mutex); - return error; + spin_unlock(&inode->i_lock); + return 0; }
void gfs2_qa_put(struct gfs2_inode *ip) { - down_write(&ip->i_rw_mutex); + struct inode *inode = &ip->i_inode; + + spin_lock(&inode->i_lock); if (ip->i_qadata && --ip->i_qadata->qa_ref == 0) { kmem_cache_free(gfs2_qadata_cachep, ip->i_qadata); ip->i_qadata = NULL; } - up_write(&ip->i_rw_mutex); + spin_unlock(&inode->i_lock); }
int gfs2_quota_hold(struct gfs2_inode *ip, kuid_t uid, kgid_t gid)